1. Field
One embodiment of the invention relates to a multilayer printed wiring board containing electronic parts, a method of manufacturing a multilayer printed wiring board containing electronic parts and an electronic apparatus having a multilayer printed wiring board containing electronic parts.
2. Description of the Related Art
Conventionally, multilayer printed wiring boards are often used in electronic apparatus. Multilayer printed wiring boards are currently made to contain electronic parts in the inside in order to raise the degree of freedom of designing the conductor pattern formed on the surface of the multilayer printed wiring board, although such electronic parts have often been mounted on the surface of the multilayer printed wiring board.
Generally, when a multilayer printed wiring board is made to contain electronic parts in the inside, the electronic parts are firstly mounted on the printed wiring board that operates as the core and an insulating layer that is typically a semi-hardened epoxy resin layer is laid on the layer of the mounted electronic parts by way of a press process. As a result, the electronic parts are contained in the inside.
In multilayer printed wiring boards of the above identified type, it is desirable that the patterns formed on the layers arranged vis-à-vis with the electronic parts to be contained in the inside interposed between them are electrically connected to each other for the purpose of raising the degree of freedom of pattern formation. However, it is actually difficult to electrically connect the patterns formed on the layers arranged vis-à-vis with the electronic parts to be contained in the inside interposed between them. This will be described below.
Generally, through holes are formed when the patterns formed in layers are to be electrically connected to each other. The through holes are made to run all the way from one of the surfaces of the multilayer printed wiring board to the other surface.
However, as pointed out above, the electronic parts to be contained in the inside are firstly mounted on the surface of the printed wiring board that operates as the core and subsequently an insulating layer is formed thereon by way of a press process to actually contain them in the inside.
Since another insulating layer is found under the layer where the electronic parts are mounted, it is difficult to form through holes only through the layer where the electronic parts are mounted and the layer arranged opposite to it. Therefore, it is difficult to electrically connect the patterns formed vis-à-vis with the electronic parts to be contained interposed between them.
Meanwhile, a parts-containing substrate of a multilayer structure of a plurality of insulating layers having bumps at terminal sections and containing electronic parts has been disclosed in Jpn. Pat. Appln. Publication No. 2002-176267.
However, the parts-containing substrate disclosed in Jpn. Pat. Appln. Publication No. 2002-176267 relates to a technique of containing electronic parts in insulating layers and is not for raising the degree of freedom of pattern formation.